A179699 Numbers of the form p^8*q^2 where p and q are distinct primes.

2304, 6400, 12544, 26244, 30976, 43264, 73984, 92416, 135424, 164025, 215296, 246016, 321489, 350464, 430336, 473344, 565504, 719104, 793881, 891136, 952576, 1108809, 1149184, 1290496, 1364224, 1562500, 1597696, 1763584

Offset

1,1

Links

T. D. Noe, Table of n, a(n) for n = 1..1000

Will Nicholes, Prime Signatures

Formula

Sum_{n>=1} 1/a(n) = P(2)*P(8) - P(10) = A085548 * A085968 - P(10) = 0.000843..., where P is the prime zeta function. - Amiram Eldar, Jul 06 2020

Mathematica

f[n_]:=Sort[Last/@FactorInteger[n]]=={2, 8}; Select[Range[10^6], f]

Prog

(PARI) list(lim)=my(v=List(), t); forprime(p=2, (lim\4)^(1/8), t=p^8; forprime(q=2, sqrt(lim\t), if(p==q, next); listput(v, t*q^2))); vecsort(Vec(v)) \\ Charles R Greathouse IV, Jul 24 2011

Crossrefs

Cf. A085548, A085968.

Sequence in context: A359321 A339349 A281927 * A195652 A256729 A204102

Adjacent sequences: A179696 A179697 A179698 * A179700 A179701 A179702

Keyword

nonn

Author

Vladimir Joseph Stephan Orlovsky, Jul 24 2010

Status

approved